Safety device for automatic platen printing press



g- 1953 r E. SCHWARZBECK 2,845,863

SAFETY DEVICE FOR AUTOMATIC PLATEN PR INTING PRESS Filed April. 11, 1955 5 Shets-Sheet 1 1958 E. SCHWARZBECK 2,845,863

' SAFETY DEVICE FOR AUTOMATIC PLATEN PRINTING PRESS Filed April 11, 1955 3, Sheets-Sheet 2 Aug. 5, 1958 E. scHwARzB EcK SAFETY DEVICE FOR AUTOMATIC PLATEN PRINTING PRESS Filed April 11, 1955 3 Sheets-Sheet 3 United States. Patent O i SAFETY DEVICE FOR AUTOMATIC PLATEN PRINTING PRESS Erich Schwarzbeck, Heidelberg, Germany, assignor to Schnellpressenfabrik' Aktiengesellschaft Heidelberg, Heidelberg, Germany, a corporation of Germany Application April 11, 1955,Serial No. 500,598

Claims priority, application Germany April 12, 1954 2 Claims. (Cl. 101-306) The present invention relates to automatic platen printing presses and particularly to safety mechanism for such presses.

In automatic platen printing presses with rotating paper grippers, it has heretofore been proposed to provide a movable guard located in front of the grippers and connected with a mechanical disengaging device in the drive of the press so. that the press, and hence the gripping movement, may be stopped by movement of the guard. With an arrangement of this kind, the disengaging device can be actuated only from the operational side of the machine since the guard by which the device is actuated is located infront of thegrippers. However, in addition to the actual printing work, it is often necessary to carry out auxiliary work on other parts of a running machine for example on the inking mechanism disposed at the rear of the machine. From this position, it is impossible to actuate the guard and hence the disengaging device. Insuch cases, the operator must go to the control panel if he wishes to stop the machine. This is a serious disadvantage, particularly if it becomes necessaryfor some reason to disengage the machine immediately.

It-is an object of the present invention to overcome this disadvantage and to provide a safety device that is operable from several sides of the machine to interrupt the drive of the press. In a particularly simple and efiective embodiment of the invention, a gripper guard is mounted on the forward end of a shaft which extends fore and aft of themachineand is connected to a disengaging'device forstopping the press. In accordance with the invention, a handle is provided on the rear end of this shaft so that the guard, and hence the disengaging device, may be actuatednot only from the front of the machine but from the rear; Preferably, one ormore further handles connected with the guard shaft are provided at the sides of the machine so that the machine can be disengaged from any side. The disengaging device is preferably provided with a locking member to prevent the re-engagement of the drive of the press until the guard has been returned to its original position. Other objects and advantages of the invention will be seen from the following description and claims in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic perspective view of an automatic platen printing press incorporating safety mechanism in accordance with the invention;

Fig. 2 is a detail showing in side elevation the mounting of the safety guard and a rear operating handle;

Fig. 3 is a schematic view showing a portion of the safety mechanism in front elevation as seen approximately from the line 3--3 in Fig. 2;

Fig. 4 is an enlarged fragmentary plan view showing a portion of the drive-disengaging mechanism;

Fig. 5 is a section taken approximately on the line 55 in Fig. 4; and

Fig. 6 is a view taken approximately on the line 6-6 in Fig. 4.

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In the embodiment of the invention illustrated in the drawings, a shaft or rod 4 extending fore and aft. of the machine is rotatably supported, for example. by a bearing portion 20 of .the frame 3. At its forward end, the shaft 4 carries a guard 2 adapted in operational position to be disposed in front of rotating paper feed and depositing grippers 1. At its rear end, the shaft 4 carries a disc or collar 5 having an eye 6 in which there is connected the core of a flexible cable 7 the other end of which is connected to a pawl 8 disposed on the drive side of the printing press. The pawl 8 is provided with an eye 8 for attachment of the flexible cable. In its normal position during operating of the press, a portion 8a of the pawl Sis engaged by theend of a stud 10 on an extension 9 of the shift lever 9 to hold the lever 9 in operative position against the tension of a spring 21. When the shaft 4 is rotatedby swinging the guard 2 in the direction of the arrow 11 (Fig. l), the flexible cable 7 acts to swing the pawl 8 about its pivot 22 from the solid line positionto the broken line position in Fig. 5, thereby freeing the shift lever 9 so that it is moved by the spring 21 in the direction of the arrow 23 (Fig. 4), thereby disengaging the drive and stopping the press.

The shift lever 9 of the press drive also carries a hook 24 which is in such position as to be engaged by a nose portion 8b of the pawl 8 when the lever 9 is in non-operative position-i. e. with the press stopped-and the pawl 8 is swung counterclockwise to the broken line position shown in Fig. 5. Hence, as long as the guard 2 is in non-operative position, the shift lever 9-is locked by the pawl 8 and hook 24 against movement in the direction of the arrow- 25-(Fig. 4) to restart the press.

When the guard 2 has been swung back to the operative position shown in Fig. 1, the lever 9 is released by the pawl '8 and may bemoved by hand, in the direction of the arrow 25 to start the press. When the shift lever 9'reaches:operative; position, the pawl 8 drops infront of the end of the stud 10 and thereby holds the shift lever in operative position. The shift lever extension 9' which carries the stud 10 is rotatable relative to the main portion of the shift lever against the action ofa torsion spring 26 which tends to hold the extension 9" in predetermined rotational position against asuitable stop: By rotation of the extension 9 against the action of spring 26, the stud 101 canbeswung outof engagement with the pawl 8' to permit movement of the shift lever 9 from-operative to inoperative position- The shift lever 9 actuates a clutch or other device for coupling. the driving mechanism of the press with. a flywheel 27, such coupling devices being known per se. By the disconnecting of this coupling device, the press can be stopped immediately without having to overcome the inertia of the flywheel.

In order that the drive may be dissengaged and preferably locked in disengaged position from the rear of the printing press as well as from the front, the control shaft 4 carries at its rear end a handle 12 by means of which the shaft 4 can be turned to disengage the pawl 8 from the stud 10 of the shift lever 9. Thus, the disengaging and locking device may be actuated from the rear of the machine, for example when work is being carried out on the inking mechanism 13.

In order to allow the machine to be stopped also from the arrow 19 (Fig. 1), an operator moves the rod 15 axially to the solid line position shown in Fig. 3, thereby rotating the control shaft 4 and stopping the machine. It will be understood that, if desired, the rod 15 is extended to the opposite si de of the machine or a similar rod is provided so that the control shaft 4 can be actuated to stop the machine by an operator on either side of the machine as well as front and back.

Figs. 5 and 6 are more detailed views of the elements 24 and 8 wherein are shown the cooperative position of the stop 10 and the pawl 8. Fig. 5 indicates generally the position of the stop 10 with respect to pawl 8 and the various positions of pawl 8 are shown in broken lines and designated as positions I, II, III, with the corresponding positions of the nose portion 8b of pawl 8 also indicated in Roman numerals in a corresponding manner. It can readily be seen that the initial position I has the stop 10 and the pawl 8 cooperating as shown, with the surface 8a of the pawl not quite centrally located on the stop 10 so that when cable 7 is actuated the pawl moves to position II while of course, the spring 21 begins to move the shift lever 9 in the direction of the arrow 23. In the event that the hook 24 engages the nose portion 8b during the movement of elements 8 and 9, the spring 21 continues to urge lever 9 in the direction indicated in Fig. 4 by arrow 23 since the leading edge of the nose portion 812 is tapered in the manner shown in the attached sketch and designated as Sbb. Moreover, the hook 24 is tapered in the manner shown in Figs. 4 and 5 of the attached drawings so that the two slanting surfaces of element 24 and nose portion 812 slidably engage, thus permitting the spring to completely move the lever 9 to an interrupting position of the power to the press. Of course, the tapered surfaces are machined in a manner permitting the slidable engagement thereof and the leading corner of the element 24 is rounded off to overcome any possibility of inaccurate machining. engages the slanted surface 8bb of nose portion 812 in the event that machining tolerances are exceeded. It will thus be seen that in this manner the slanted surfaces of 8b and element 24 cooperate. The lever 9 has been moved to its proper disengaging position in the position shown by the broken lines in Fig. 4, the pawl 8 assuming position III as shown in Fig. 5 of the drawing.

It will thus be seen that the present invention provides an extremely simple, yet highly effective, safety mechanism for stopping the machine by means of a disconnecting mechanism which is operable not only from the front of the machine but also from the rear and side. While a preferred embodiment of the invention has been illustrated in the drawings and specifically described, it will be understood that modifications may be made and that the invention is in no way limited to this particular embodiment.

What I claim and desire to secure by Letters Patent is:

1. In an automatic platen printing press having grippers for feeding and depositing the sheets of paper to be printed, power means for driving the press, a dis engaging device for interrupting the drive of the press and a mechanical locking device for preventing re-engagement of the drive of the press, a displaceable guard disposed at the front of the press in front of said grippers, a manually displaceable handle mounted on a rear portion of the press, said guard and handle being movable from an operating position to a non-operating position, means operably connecting said guard and hnadle to said disengaging device to stop the press upon movement of either said guard or handle to non-operating position and for releasing said locking device only when both said guard and said handle are in operating position.

2. In an automatic platen printing press having grip pers for feeding and depositing the sheets of paper to be printed, power means for driving the press and a disengaging device for interrupting the drive of the press, a rotatable shaft extending fore and aft of the press, a guard mounted on the forward end of said shaft and fixed to the shaft so that said shaft is rotatable by movement of said guard, means operably connecting said shaft with said disengaging device to interrupt said drive upon rotation of said shaft, 21 first displaceable handle connected to said shaft and disposed at the rear of the press for rotating said shaft to disconnect said drive, at least one other displaceable handle disposed at a side of the machine and connected with said shaft to rotate said shaft and thereby disconnect said drive, said Thus, the rounded corner of element 24 other handle comprising a rod movable in a generally lengthwise direction and slidably connected to an arm fixed on said shaft to rotate said shaft by generally lengthwise movement of said rod, a mechanical locking device for preventing re-engagement of the drive of the press, and said means connecting said shaft with said disengaging device including means to release said locking device only when said guard and said handles are in operating position.

References Cited in the file of this patent 7 UNITED STATES PATENTS 751,873 Rockstroh Feb. 9, 1904 2,678,602 Kunz May 18, 1954 FOREIGN PATENTS 318,515 Great Britain June 26, 1930 491,193 Great Britain Aug. 29, 1938 

